Typically leader systems are used to drive piles, drilling or augered pile operations and are mounted to various power units such as excavators, cranes, boom trucks or tracked machines. The leader system is responsible for guiding the hammer, drill or drive head so that it is in alignment with the pile or drilling operation. Depending on the construction a telescoping lead may be desirable. Telescoping leader systems can therefore telescope the leads either upwards or downwards. There ability to telescope either upwards or downwards depends on what the leader system is mounted to. When mounted to a crane or boom truck, the telescoping leads can move either up or down depending on orientation, however when mounted to an excavator the telescoping leader system would typically telescope upwards.
Traditional telescoping leader systems are cumbersome in that they telescope in a staged fashion, telescoping each segment out in front of each other in a stepped fashion so that segments are not along the same axis. This arrangement does not allow the leader system to be easily removed from the power unit and is not an appropriate configuration for a crane. Most leader systems for cranes have a fixed length and utilize extensions that allow for longer piles to be installed.
Prior art telescoping leader systems have been devised to address the noted problems. For example, U.S. Pat. No. 3,035,646 which issued May 22 1962 to Johansson discloses an improved pile driving attachment including a pile driving lead for use with a caterpillar or like tractor crane having a windlass frame preferably in the form of a turn-table or rotatable crane house which is carried by the under frame of the tractor. The invention further discloses a series of extendable or telescoping struts that may extended by a hydraulic system.
U.S. Pat. No. 3,388,317 which issued on Jun. 10, 1975 to Walters discloses a system for supplying full hydraulic power to the movable components of a positioning apparatus of a pile driver or similar apparatus. The device includes hydraulically drive truss sections that form the spotters for the invention which can both extend and retract.
Thus a telescoping leader system having the ability to be quickly mounted and removed from an excavator, crane, boom truck, that can install longer piles with less power and is compact in nature, is desirable.